Initial Configuration and Options

Having accepted the Windows 8 license, the option to do an "Upgrade Install" or "Custom Install" is given:

Upgrades from previous versions of Windows are often a bad idea and it is usually much better to do a fresh installation and configure a system from scratch. As this trial software is only valid for 90 days, you should be doing a "Custon Install" onto a blank system, so click the "Custom" area of the screen to proceed.

Now, Windows displays a list of the drives found where Windows may be installed. Examine this list to ensure it agrees with what you expect. If you have two drives configured as a hardware RAID-1 (mirrored) pair, then only a single drive should be seen at this stage.